This invention relates to packaging and more specifically to apparatus for folding the end closures of cartons of the type which include a pair of gusset closure panels.
U.S. Pat. No. 4,046,308, issued Sept. 6, 1977, discloses such an end-sealing package which is designed to provide a totally moisture-resistant inner barrier within an outer paperboard carton. The package is formed from a laminated blank wherein a moisture-resistant film material having heat-sealing characteristics, such as polyethylene film, is adhered to a fiberboard substrate by a heat-weakenable laminant, such as microcrystalline wax. The blank may be formed by die-cutting sheets or rolls of such a lamination so that the two layers will be substantially coextensive. During the formation of the blank into a tubular body by side-seaming and subsequentially during the heat-sealing of the end closures, portions or panels of the fiberboard substrate are separated from the inner lining by selective heat delamination.
Apparatus for closing and sealing the ends of packages of this general type, which is illustrated in the aforementioned U.S. patent, takes the form of a pair of synchronized, intermittently rotating turrets, each of which has a plurality of pocket members into which individual cartons are received. More versatile apparatus for closing and sealing such packages has been found desirable.